Robert G. Dosch

Selective adsorption and ion exchange of metal cations and anions with silico-titanates and layered titanates

Metal ions may be removed from aqueous wastes from metal processing plants and from refineries. They may also be used in concentrating radioactive elements found in dilute, aqueous, nuclear wastes. A new series of silico-titanates and alkali titanates are shown to have specific selectivity for cations of lead, mercury, and cadmium and the dichromate anion in solutions with low and high pH. Furthermore, one particular silico-titanate, TAM-5, was found to be highly selective for Cs+ and Sr2+ in solutions of 5.7 M Na+ and 0.6 M OH−. A high potential exists for these materials for removing Cs+ and Sr2+ from radioactive aqueous wastes containing high concentrations of Na+ at high and low pH.

Synthesis and catalytic activity when using a type 2 titanate

Abstract The synthesis of Type 2 crystalline sodium aluminum titanate (T2CT) was optimized, and techniques for scale-up from 3 to 100 grams per batch were developed. On scaling to 100 g batches the surface area decreased from 207 to 160–170 m 2 g , but all other properties such as X-Ray diffraction patterns, elemental composition, ion exchange capacity, and stability remained the same. Four sources of aluminum, aluminum nitrate, aluminum chloride, aluminum isopropoxide, and aluminum butoxide, were used in the synthesis, and no apparent change in the material occurs. The composition, ion exchange capacity, and effective difiusivity for hexane vapor measured at 22 ° C for the T2CT was determined to be Na0.47Al0.02TiO2.265, 4.4 meq g , and 1.2 × 10−11 m 2 s , respectively. Calcination at 535 °C resulted in a slight decrease in the d0-spacing from 1.0 to 0.9 nm, and formation of the crystalline phase, Na0.23TiO2. At 600 °C the only crystalline phase remaining was Na0.23TiO2. When add exchanged T2CT was used as a support for a sulfided NiMo catalysts, the activity for hydrogenation of pyrene was 1.22(g Mo)−1s−1 for particle size of −100 mesh. For two commercial catalysts, Shell 324 and Amocat 1C, the activities were 1.2 and 1.45 (g Mo)−1 s−1 for −200 mesh, respectively. Effective diffusivities of 6.5 × 10−12 and 3.2 × 10−11 m 2 s for pyrene at 300 °C were obtained for Shell 324 and Amocat 1C commercial catalysts, respectively.

Radionuclide Migration Studies Associated with the WIPP Site in Southern New Mexico

Migration of radionuclides in ground water has been identified as the most likely pathway from a deep geologic nuclear waste repository to the biosphere. An important mechanism in retarding nuclide movement in ground water is sorption, a term which is used herein to encompass all mechanisms pertinent to interactions (which include ion exchange, absorption, and precipitation) between nuclides and the geomedia. Water exiting a repository at the WIPP site would encounter halite in the repository horizon, polyhalite and anhydrite beds, and finally sandstone and dolomite formations which are the upper bound of the repository. To a rough approximation, the concentration of a given nuclide per unit mass, C(solid), sorbed on a solid mineral phase can be related to the concentration per unit volume, C(liquid), in the liquid phase by the relation:

High liquid yields from bituminous coal via hydropyrolysis with dispersed catalysts

C\left( {solid} \right) = Kd \cdot C\left( {liquid} \right)

Hydrous metal oxide ion exchangers for preparation of catalysts for direct coal liquefaction

where Kd is generally referred to as the distribution coefficient, with units of ml/g. The use of the term Kd implies an equilibrium state for a given reaction and is used, in that sense, in the mathematical modeling of long term radionuclide migration (1). In the interaction of a nuclide with a complex mineral assemblage, equilibrium conditions may not apply, and the symbol Kd is used as an empirical value applying only to the particular set of conditions used.